Flexidrive®

Propulsion systems based on semi-submerged propellers have traditionally been considered efficient on light, powerful boats, but inadequate for slower and heavier ones.

Only a few believed in the great possibilities this system offers, which actually, when properly designed, can be adopted with notable advantages to any boat type, even commercial displacement ships.Elica di superficie

Indeed, cargo ships with partially immersed propulsion systems have performed extremely well as far as propulsive efficiency is concerned and demonstrated significant savings on fuel compared to traditional ships. Especially decisive for research progress in this field was the work of designer Renato “Sonny” Levi, with whom Flexitab has established important scientific cooperation.

For over ten years, infact, Flexitab has energetically committed itself studying and developing semi-submerged propulsion, thanks the Victory Design’s activities. The fruitful collaboration between these entities has made possible a series of projects, important milestones in the development of semi-submerged propulsion and its range of applications. This allowed the setting up of the Flexidrive®, a complete range of partially immersed propellers adapted to different types of boats.

A pleasure boat that was very important for research in semi-submerged propulsion was the Dart, a 46’ mono-hull totally designed by Victory Design. The Dart, with two 600-horsepower diesel engines, reached a maximum speed of 48 knots, registering around 10 knots more than any other boat of equal displacement propelled by immersed propellers.

But the most encouraging features of the Dart prototype were its harbour manoeuvrability and during the navigation, which were absolutely equivalent to traditional propulsion systems, as was its minimum planing speed of around 12 knots.

The semi-submerged propeller system thus demonstrated a significant increase in propulsive efficiency, stimulating further research in the field.

With the aim of going all the way in the study and development of semi-submerged propulsion, the experience built up by Flexitab and Victory Design converged in a research program called Flexidrive, which is supported by the Ministry for Manufacturing Activities and the European Union and by fundamental cooperation with the Department of Analysis and Structural Design and the Department of Naval Engineering of the Engineering Faculty of the University of Naples Federico II and the Department of Naval Engineering of the University of Genoa.

Out of this project the Flexidrive® family of propellers was born. This is a revolutionary system based on the principle of semi-submersed propellers, using supersonic flow, divided into three categories of application: Energy, Power, Speed, which can be applied to all types of boats.

Flexidrive P700 P700 Boomex propulsione nautica con elica di superficie
Flexidrive Power 700 Flexidrive Power 700 Boomex

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Flexitab Boomex

TECHNICAL DATA FLEXIDRIVE® POWER P700
Indicative power range [hp] Up to 700
Max torque* [lbft] 3024
Shaft diameter [in] 2.95
External length [in] 50
Body width [in] 42,3
Drive height [in] - – - – -
Max propeller [in] 30,31
Rudder angle Dx = 35°; Sx = 35°
Materiali
Body Composite
Thrust unit Lightweight aluminium alloy with anticorrosion treatment
Rudder blade Bronze

* This data refers to Pleasure Duty use.

Flexitab reserves the right to change the data listed above at any time without prior notice.

Propulsione P2000 Flexitab Power P2000 drive
Flexidrive power 2000

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TECHNICAL DATA FLEXIDRIVE® POWER P2000
Indicative power range [hp] up tp 2000
Max torque* [lbft] 12000
Shaft diameter [in] 3,74
External length [in] 69,40
Body width [in] 62,99
Drive height [in] 41,73
Max propeller [in] 43,30
Rudder angle Dx = 35°; Sx = 35°
Materiali
Body Composite
Thrust unit Lightweight aluminium alloy with anticorrosion treatment
Rudder blade high-resistance stainless steel

* This data refers to Pleasure Duty use.

Flexitab reserves the right to change the data listed above at any time without prior notice.

Video Flexitab – FlexiDrive

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